<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="./styles/index.css" />
    <title>Document</title>
  </head>
  <body>
    <div id="app" class="score-case">
      <div class="table">
        <table>
          <thead>
            <tr>
              <th>编号</th>
              <th>科目</th>
              <th>成绩</th>
              <th>操作</th>
            </tr>
          </thead>
          <tbody v-if="list.length">
            <tr v-for="(item,index) in list" :key="item.id">
              <td>{{index+1}}</td>
              <td>{{item.subject}}</td>
              <td :class="{red:item.sc < 60}">{{item.score}}</td>
              <td><a href="#" @click.prevent="del(item.id)">删除</a></td>
            </tr>
          </tbody>
          <tbody v-else>
            <tr>
              <td colspan="5">
                <span class="none" >暂无数据</span>
              </td>
            </tr>
          </tbody>

          <tfoot v-if="list.length">
            <tr>
              <td colspan="5">
                <span>总分:{{total}}</span>
                <span style="margin-left: 50px">平均分:{{avg}}</span>
              </td>
            </tr>
          </tfoot>
        </table>
      </div>
      <div class="form">
        <div class="form-item">
          <div class="label">科目：</div>
          <div class="input">
            <input type="text" v-model.trim="subject" placeholder="请输入科目" />
          </div>
        </div>
        <div class="form-item">
          <div class="label">分数：</div>
          <div class="input">
            <input type="text" v-model.number="score" placeholder="请输入分数" />
          </div>
        </div>
        <div class="form-item">
          <div class="label"></div>
          <div class="input">
            <button class="submit" @click="add">添加</button>
          </div>
        </div>
      </div>
    </div>
    <script src="../vue.js"></script>
    <script>
      const app = new Vue({
        el: "#app",
        data: {
          list: [
            { id: 1, subject: "语文", score: 20 },
            { id: 7, subject: "数学", score: 99 },
            { id: 12, subject: "英语", score: 70 },
          ],
          subject: "",
          score: "",
        },
        computed:{
          total(){
            return this.list.reduce((sum,item)=>sum+item.score,0)
          },
          avg(){
            return this.total / this.list.length
          }
        },
        methods: {
          del(id) {
            this.list = this.list.filter(item => item.id !== id);
          },
          //添加
          add(){
          //1.判断
          if(!this.subject ||!this.score){
            alert('输入内容不能为空')
            return 
          }
          if(this.score<0 ||this.score>100){
            alert('输入内容在0-100之间')
            return 
          }
          //2.包对象插入
          this.list.push({
            id:Math.floor(Math.random() *10000),
            subject:this.subject,
            score:this.score
          })
          //3.清空输入框
          this.subject = ""
          this.score=""
          }
        
        },
      });
    </script>
  </body>
</html>
